Method of and apparatus for the construction of roads



vApril 17,1945. E. L. HARRINGTON I I 2,373,828

I METHOD OF AND APPARATUS FOR THE CONSTRUCTION OF ROADS Filed March 19,1940 7 l0 ShQetS-She9t l April l945.- HARRINGTON 2,373,828

METHOD OF AND APPARATUS FOR THE CONSTRUCTION OF ROADS Filed March 19,1940 10 Sheets-Sheet 2 ILI:

lNVENT OR April '17, 1945. E. HARRIINGTON v METHOD OF AND APPARATUS FORTHE CONSTRUCTIONOF ROADS 1940 10 shee cs-sheet 5 Filed March 19 v r L13$ v 5' m hm Sm Q IN V E N TO R fowaro Lf/al'r/hgfan m m M M Q N I l lI l l l ill T: 1 .1 NM E w W mm. l||llfliiwullll a RN R1: fi H l HHuulun INHHHHHMMHHUHN WMW hWW I i f Li r Cr a w. %N 5 3 o n J F w m a w RN mm. RM.- Q.

April 17, 1945. v E. HARRINGTON A 2,373,828

METHOD OF AND APPARATUS FOR IfHE CONSTRUCTION 0F ROADS Filed March 19,1940 10 SheetsShet 4 INVENTOR April 1945. v E. LAHARRINGTON I 2,373,828

METHOD OF AND APPARATUS FOR THE CONSTRUCTION OF ROADS Filed March 19,1940 A 10 Sheets-Sheet 5 IINVENTOR I [dn amL/rarringfm v M M E. L.HARRINGTON 2,373,828

METHOD OF AND APPARATUS FOR THE CONSTRUCTION OF ROADS April 17, 1945.

' Filed March 19, 1940 10 Sheets-Sheet 6 April 1945- I E. L. HARiTINGTON2,373,828

METHOD OF AND APPARATUS FOR THE CONSTRUCTION ROADS Filed March 19, 19401o Sheets-Sheet '1 c: )I 20 :1; flgll o o I 12 INVENTOR Ap 1945- E.HARRINGTON I 2,373,828

METHOD OF AND APPARATUS FOR THE CONSTRUCTION OF ROADS Filed March 19,1940 10 Sheets-Sheet INVENTOR April 17, 1945. 'E. HARRINGTON 2,373,828

METHOD OF AND APPARATUS FOR THE CONSTRUCTION OF ROADS Filed March 19,1940' 10 Sheets-She et 9 Y April 17, 1945- E. HARRI'IVNGTON METHOD OF.'AND APPARATUS FOR THE CONSTRUCTION OF ROADS Filed March 19, 1940 10Sheets-Sheet 10 M 15w A 2 NW N w% v/ mm MA it Q A \H W, a a g. 5 (a: 3%NE llll NQ E Patented Apr. 17, 1945 METHOD OF AND APPARATUS FOR THECONSTRUCTION OF ROADS Edward L. Harrington, Pittsburgh, Pa., assignor toBlaw-Knox Company, Pittsburgh, Pa., a corporation of New JerseyApplication March 19, 1940, Serial No. 324,755

, 11 Claims.

This invention pertains to the art of paving and is for a method andapparatus. for the spreading of concrete in the laying of roads or likepaving operations.

The present practice in the building of concrete roads is to place formrails along each side of the lane to be paved after the grading has beencompleted. Sometimes the lane is the full width of the road to beconstructed, but more frequently the road is constructed of parallellanes 8 to 12 feet wide. Concrete is dumped between these rails, spreadby any suitable means, and the surplus pushed forward by some kind of astrike-off so as to leave an approximately level but unfinished surfacea few inches below the desired top surface. On this surface steelreinforcing rods or mesh are placed, and concrete then placed above,spread, and the surplus again pushed forward, usually by a finishingmachine which at the same time smooths and irons the surface as closelyas possible to the final requirement.

Hitherto it has been customary for preliminary spreading of the concreteto be done by apparatus on the concrete mixer itself; but recently,especially on large paving operations requiring the placing of a largeyardage and employing more than one mixer, especially where the work isconducted in a narrow lane, the practice has grown customary for themixer to dum the concrete more or less indiscriminately between the roadrails, taking care only to provide a sufficient quantity and to avoidtoo large a surplus. leaving the spreading as well as the pushingforward of the surplus to be accomplished by other means.

Accordingly, lateral spreading is done by hand or special Spreaders. andthe striking off and moving forward of the surplus so as to leave theconcrete approximately level for the steel reinforcement by strike-oilmembers pushed by various means. The so eeds of the finishing machines,which usually oscillate transversely of the road, push forward thesurplus concrete for the final finishing process only; and as would beanticipated, the amount of this surplus concrete varies greatly bothfrom point to point longitudinally along the road but also from point topoint transversely of the road, when in contact with the screed. Becausethe material has some fluidity, it will rise back of the screed to someextent. depending on the height of the surplus material in front of thescreed. Variations in the distribution of surplus material in front ofthe screed accordingly produces some corresponding variation in thesurface back of the screed, these variations being manifested astransverse and longitudinal waves in the surface.

According to the present invention I provide an apparatus for spreadingthe concrete transversely over the distance between the rails, I alsoprovide a method and apparatus whereby a pile of surplus concrete ismoved back and forth across the surface of the road between the rails asthe apparatus is advanced thus spreading and leveling the concrete. Iprefer that this means for moving the concrete back'and forth also workthe pile of material forwardly in the direction of the movement of theapparatus as it is carried back and forth. Moreover, I prefer to providea method and apparatus wherein a scraping or leveling operation in aforward direction follows the first transverse scraping of material,there being a screed or other transverse strike-off means back of thetransversely moving scraper to further spread and even off the surfaceof the concrete, the back and forth scraping operation, however, beingeffected in such a manner as to prevent the building up of anyundesirable surplus of concrete in front of the screed or strikeoifwhereby only a surplus of concrete is maintained in front of the screedsufficient for the most effective operation of the screed. By thusmaintaining a controlled surplus in front of the screed, resistance toforward movement of the screed is substantially uniform, and since thedepth of surplus material in front of the screed or strike-off iscontrolled and kept substantially constant along the length of thepaving and 7 crosswise of the screed, waves in the surface back of thescreed due to variations in the distribution of material in front of thescreed are substantially completely avoided.

According to a. preferred embodiment of my invention there is provided asupporting frame mounted on wheels for movement along the form rails ateach side of the roadway being built. This supporting frame is providedwith a transverse runway along which a transversely movable carrier ortrolley may b reciprocated. A scraping means depends from the carrier ortrolley and means is provided for raising and lowering the scrapingmeans so as to determine the thickness of the bed of concrete beinglaid. Power driven means is provided for moving the trolley back andforth along its runway, and

mechanism is provided whereby as the trolley approaches each limit ofits travel, the position of the scraping means with respect to the pileof material being scraped is shifted so that the scraping means will bemoved at the limit of movement of the trolley from a position where itis facing toward an outside rail of the road to a position where it isfacing toward the middle of the road.

Mounted on the supporting frame back of the trolley is a verticallyadjustable screed which is preferably provided with a vibrator, the sceed being parallel to the runway along which the trolley movesand beingpositioned a predetermined distance back of the path of travel of thescraper so that the transversely movable scraper determines the toe ofthe pile of surplus material in front of the screed- A power plant ismounted on the supporting frame'and there are connections fortransmitting power from the power plant to the trolley. There are alsoconnections for driving the carriage along the rails operated from thesame power plant whereby the back and forth movement of the trolley iscorre-.

lated to the travel of the frame along the road bed. Another drivingconnectlon transmits power from the power plant to the vibrating screed.

My invention may be more fully imderstood by reference to theaccompanying drawings in which Figure 1 shows a top plan view embodyingmy invention;

Figure 2 is a side elevation of the machine shown inFigure 1;

Figure 3-is a rear end view of the machine shown with the screed beingbroken away to show the scraper which is located in advance of it;

Figure 4 is a detail view showing a part of the of a machine asvasasmechsnism,shown in Figure 15 in which one of-thespresderbladesisdowmandl lgure l'l-isasimilarsectionin whichtheoppositescrsperbladeisshowninelevated osition.

Referringflmttoliguresltollinclusive,themachhiecomprlsesairamedesignatedgenerallyaslformedofstructuralmetalmembers. Itis with two front, wheels 3. one ateach sideofthemschineandtworearwheelsl,'one ateachsideofthemachine.Thesewheelsare flangedtorollalong atrackpmvidedbytheformsAateachsideofthepavement.

Extendingacrossthefullwidthofthe frame are two spaced-apart channelmembers 5 and 6 Y which form a runway for a carrier or trolley deschaindrive through which the trolley or carrier for the scraper isreciprocated;

Figure 5 is a transverse section through the trolley and that portion ofthe machine which provides the runway for the trolley, the view being insubstantially the plane of line V-V of Figure l;

Figure 6 is a horizontal section in the plane oflineVI-VIofFigure 5;

Figure 7 is a fragmentary view showing a front elevation of a portion ofthe frame of the ma,- chine with the trolley and scraper;

Figure 8 is a detail view of the scraper itself, the view being a sideelevation of the scraping blade;

Figure 9 is a schematic view showing various portions -of the scraper inrelation to the travel of the trolley, the view being a top plan view;

Figure 10 is a diagrammatic view showing the swinging movement of thescraper from one position to the other, the view being also a plan view;

Figure 11 is a transverse vertical section through that portion of themachine which supports and braces the screed and through the screeditself; V

Figure 12 is a front elevation showing a modifled form of scraper inwhich the scraper has two blades instead of one;

Figure 13 is a transverse section through th mechanism shown inFigure12, the view bein substantially in the plane of line XIII-XIII of Figure12;

Figure '14 is a side elevation of a machine embodying the constructionshown in Figures 12 and 13;

Figure 15 is a front View showing another form of spreader or scraper;

Figure 16 is a section through one side of the ignated generally as I.There is an open space (seeFigure 1) Ibetweenthetwochannelsi and 8providing a clearance for the trolley and the parts which are carriedthereon.

Extending crosswise of the machine to the rear of the channel 6 is astructural member II, and byreferencetoFigure 11 itwillbeseenthatth-zstructural member II is provided with an upright supporting frame ii.The upright supporting structure ll, formed of the several spacedapartuprights, is provided at intervals across the widthof the machine withbearings 12 for a rock shaft ii. The rock shaft I3 is provided with armsi4. Depending from the arms ll are adjustable links l5, and the lowerends of the links I! are connected through vibration dampeningconnections at Ii to a box-like screed i'l within which is a vibratingmechanism iii. The general construction of the screed and of thevibrating mechanism may be similar to that disclosed in the copendingapplication of William M. Venable. Serial No. 291,711 filed August 24;1939. Connected to one of the arms I4 is an upwardly extending link i!the upper end of which is threaded and which passes through a nut 20carried on the support II and which has an operating crank 2| thereon,the arrangement being such that when the crank 2| is turned, the nut 28will move the link I! up and down thereby rock- 'ing the arm II and theshaft I! to correspondingly raise and lower the screed. An indicator 22moving alon a calibrated scale 23 shows the height of the screed. Forpermitting the vertical adjustment of the screed while resisting thethrust to which the screed is subjected in the forward travel of themachine, adjustable parallel links 2| pivotally secured to brackets atthe back of the screed are provided, the rear ends of these links beingpivotally attached to suitable structural members 25 rigidly carried onthe frame.

The vibrating member It includes a powerdriven shaft 2 with eccentricelements thereon (not shown) so that when the shaft is rotated at highspeed, the screed as a whole will be vibrated. The vibration dampeningconnections I! serve to prevent this vibration from being transmitted,at least to any substantial intensity, to the frame 0f the machine, andit should also be stated that 21 .(see Figures 1, 2 and 3). At is atransmission through which power from the engine is provided for movingthe trolley back and forth along its runway, for driving the wheels 3and 4, and for vibrating the screed. This drive which forms no part ofmy invention per se transmits power to two shafts 2 5 and best shown inFigure 3. Shaft I0 drives a sprocket wheel II to drive a chain 32 (seeFigure 2) which chain passes around sprocket wheels for driving thewheels I and 4 on one side of the machine. Shaft 2! drives a similarsprocket wheel 3| which in turn drives a chain 32 for driving the othertwo wheels 3 and 4 at the other side of the machine. The wheels on oneside of the machine are preferably geared to the source of powerseparately from the wheels on the other side of the machine in orderthat one side of the machine may be driven faster than the other ingoing around a ciu've. \The power plant also drives a pulley I! (seeFigure 3) which drives belts 34 for transmitting power to the shaft 25of the vibrator in the screed. This power transmitting mechanism to thevibrator constitutes no part of the present invention and is more fullyshown and described in the said copending application of William M.Venabl and is merely referred to here for the purpose of fullyunderstanding the general construction of the machine.

In the construction of the machine illustrated in Figures 1 to 11inclusive, the power plant serves to further drive a shaft 35 (seeFigure 1) having a sprocket 31 thereon (see Figure 4) which sprocketdrives a second sprocket 35 through a chain 39. The sprocket 38 is keyedto a disk 40 through a shear pin 4| (see Figure 1) so as to drive ashort shaft 42 having a sprocket wheel 43 at its forward end. Atrolley-operating chain 44 passes around the sprocket wheel 43. Adjacentthe opposite end of the runway for the trolley there is a sprocket wheel45 around which the chain 44 passes, the sprocket wheel 45 being carriedon an adjustable bracket 46 (see Figures 1 and 4) through which a propertension on the chain 44 can be maintained.

The chain 44 is provided for moving the trolley 1 back and forth, andthe transversely movable scraper for spreading the concrete is suspendedfrom this trolley. The scraper may take a number of different forms andmay be operated in a number of difierent ways. The particular scraperand drive for the trolley shown in the form of the machine illustratedin Figures 1 to 11 is fully shown and described in'the copendingapplication of Charles A. Long, Serial No. 353,860 filed August 23,1940.

The trolley 1 comprises a suitably constructed frame 50. It is providedon its forward side with two spaced-apart rollers 5! which extend intothe channel 5 and which roll along the inside of this channel as atrackway. The frame 55 is also provided with two flanged upper rollers52 which travel along the top of the channel member 5. The frame islikewise provided with two flanged rollers 53 positioned below therollers 52 and which bear against the underside of the channel 5. Thisgeneral construction is best shown in Figure 5 and by this arrangementthe trolley may move back and forth along its runway but is restrainedfrom vertical movement in the runway.

The trolley is provided with a vertical sleeve 54 at the center thereof.A post 55 passes through this sleeve. To the lower end of this post issecured a scraping blade 55. The top of the post 55 is threaded andthere are two large hand wheels or nuts 51 and 58 through which thethreaded upper end of the post 55 is screwed. The hand wheel 51 isprovided for raising and lowering the post 55 to raise and lower thescraper 55, and the hand wheel 58 is provided as a lock nut for the handwheel 51. To change the elevation of the scraper 55 the hand wheel 58 isfirst turned to back it away from the hand wheel 51 after which the handwheel 51 is turned to raise or lower the post 55. When the scraper is atthe desired elevation, the hand wheel 58 is tightened down against thehand wheel 51. This arrangement allows the scraper to be adjustedvertically to any given elevation within the range provided for andleaves the post 55 free to rotate so that the position of the scrapermay be changed.

For moving the trolley back and forth the chain 44 is provided with aspecial link which carries a transverse pin 50 which may be clearly seenin Figures 5, 6 and 9. Supported on the frame of the trolley is avertically slotted guide 6| into which one end of the pin projects, andopposite the guide BI is a slotted upper guide 52 and a slotted lowerguide 63, the guides 52 and 53 being directly opposite the guide 5| andbeing in alinement with each other. The other end of the pin 80 isadapted to extend into one or the other of these guides 52 and 53. Thearrangement is such that one end of the pin 50 is always in the guideway5| and the other end of the pin 60 is either in the' guide 52 or 53except at the time that the link carrying the pin 60 is passing aroundone of the sprockets 43 and 45. When the pin is moving along the upperreach of the chain, it moves the trolley in one direction. As it passesaround one of the sprockets 43 or 45, its movement is principally in avertical direction and when it is in the lower reach of the chain, thetrolley is of course moved in the reverse direction. The mechanismdescribed provides a sim ple arrangement whereby the trolley may bemoved back and forth along its runway while the chain 44 is drivencontinuously in one direction. In order to guide the pin 60 when it ispassing around the sprocket and is between the upper and lower guides 82and 53, the frame of the machine is provided as shown in Figures 1 and 9with fixed guides 450, the purpose of which is to prevent the pin fromtwisting or pulling out of line.

In the operation of the scraper illustrated, the scraper is dragged backand forth by the back and forth movement of the trolley. As it nearseach limit of its travel it is swung in such a manner as to pass fromone side of the pile which it is pushing to the other side of the pileso that when the movement of the trolley is reversed, the mass ofmaterial being pushed by the scraper will be carried along in thereverse direction. Preferably, as shown in Figure 9, the scraping blade56 is at an angle to the direction of travel of the trolley so that itnot only carries the material sideways but tends to shove it forwardly.The scraper is in a predetermined spaced relation to the screed so thatthe inner end of the scraper determines the toe of the material whichmay pile up in front of the scraper, which in turn limits the height ofthe pile of such material. This is illustrated in Figure 11 wherein B isthe layer of concrete and S is the surplus in front of the screed.

For reversing the position of the scraper the post 55 is provided with ahorizontally projecting arm 84 which is perpendicular to the plane ofthe face of the scraper. The forward end of this arm is provided with aroller 88 best shown in Figures 5 and 6. Secured to the underside of theframe of the machine forwardly of the runway and spaced inwardly fromeach end of the runway are fixed abutments or striking plates 88A and663. These may be formed simply from pieces of angle iron welded to theunderside of the frame of the machine with one leg of the angleprojecting downwardly. These striking plates are so positioned as to beengaged by the roller 65 on the end of the arm 84 as the trolley.

Figure 9. The trolley will continue to move toward the right but as theabutment cannot move further in this direction, the further movement ofthe trolley will cause the arm 64 to transmit a rotating motion to thepost 85 causing the inner edge of the scraper to move away from thescreed. At one position in its movement the scraper will be parallelwith the screed as shown in the dotted line position X in Figure 10.Further movement of the trolley toward the right as viewed in Figure 9causes this rotary motion of the post 88 to be continued untiltheposition of the scraper has been reversed and the parts are in theposition shown at X The stop or striking plate "A is so positioned thatthe reversing movement of the scraper will be completed at the time thatthe trolley is at the furthest limit of its movement toward the right asviewed in Figure 9 at which time the transverse pin 60 on the chain willbe passing through the fixed chain guide it. The movement of the trolleywill then reverse and the scraper will be dragged toward the left untilthe roller 65 engages the striking plate 888, and as the travel of thetrolley continues toward the left, the blade will be again reversed tothe position shown at X.

It will be observed that the trolley is moving as the position of thescraper is changing so that the scraper in swinging into the positionshown at X in Figure 10 and then swinging to the reversed position,travels from one side of the pile which is being pushed by the scraperto the other. The length of travel of the trolley and the position ofthe striking plates 68A and 68B is such that the scraper will swing outclose to the rails A thus assuring of the spreading of the material evenclose to the rails, especially as the scraper will sweep some of thepile of material close to the rail around with it.

In order to hold the scraper from changing its position except adjacentthe limits of travel of the trolley, a latch mechanism is provided. In

the embodiment of the invention illustrated there are two similar latchelements 88, one being at the biasing force of the spring 88 until theshoulder 880 of the latch snaps over the arm. One or the other of theselatches holds the am to prevent the scraper from being turned. on theunderside of the frame adjacent the striking plates 88A and 68B are camsI8. Secured to the underside of the frame of the machine adjacent thestriking plates 88A and 88B are cams 18A and "B respectively. Each ofthe operating extensions 88b of the latches 88 is provided with a roller88d for cooperation with one of these cams. As best shown in Figure 7,when the roller 88d of the left-handlatch rides under the cam "A, thelatching terminal 880 of the latch will be raised out of engagement withthe arm .88.. This will occur at just the moment when the roller 88 onthe end of the arm 88 is striking the abutment 68A. This releases thelatch to permit the scraper to turn. When the scraper is nearing theopposite limit of its turning movement, the arm 84 will engage under theother latch, which in Figure '7 would be the right-hand latch, and thescraper would thus be locked until the right-hand latch engaged itsreleasing cam 18B. Stops a (see Figure 6) prevent the arm 84 fromswinging beyond the latching position.

As hereinbefore stated, the specific mechanism for operating the trolleyand for turning the scraper i the invention of Charles A. Long and isdescribed in the copending application filed by him, it beingcontemplated in my invention that any type of scraper may be moved backand forth through any suitable mechanism so long as the scraper ismanipulated in such a way as to pass from one side of the pile to theother adjacent the limits of travel of the trolley.

Another example of a scraping mechanism which may be used in myinvention is illustrated in Figures 12, 1'3 and 14. In the modificationshown in Figures 12, 13 and 14, I5 designates a trolley which is movableback and forth along a runway 18 provided on the frame of the machine.Carried on the underside of the trolley 15 is a shaft 11. Hung from theshaft TI is an archshaped frame 18 having scrapers I8 along the twoedges thereof. Secured to each end of the shaft I1 is a segment-shapedmember 88 having a gear rack 8| on its periphery. Supported on thetrolley is a transverse shaft 82 having a pinion 88 at each end thereof,the pinions 83 engaging the racks 8| on the members 80. By rotating theshaft 82 in one direction or the other, the shaft 11 may be rotatedthrough a limited arc to tilt one or the other of the two scrapingblades 19 down into scraping position. In the specific arrangementshown, the shaft 82 is operated by .means of a sprocket 85 secured tothe center of the shaft 82. A sprocket chain 86 is guided around the topof the sprocket wheel 88, the return reach of the chain passing throughthe carriage clear of the sprocket. The chain 88 is guided oversprockets 81 adjacent each end of the runway and one of the sprockets 81may be driven in the manner previously described except that with thisarrangement the chain is driven in a reverse direction instead ofcontinuously in one direction. The reversing movement of the drivingsprocket 81 may be accomplished mechanically or manually'a will bereadily unde stood by those skilled in the art. The trolley I8 isprovided with stops 88 positioned to be engaged by the terminal portionsof the arch-shaped scraper 18, as is clearly shown in Figure 12.

In the arrangement shown in Figure 12, it may be assumed that the chain88 is traveling in the direction of the arrow. At this time therighthand scraper is elevated against its stop II and the left-handscraper is in scraping osition. When the trolley reaches the limit ofits travel, the direction of the chain is reversed. The reversingmovement of the chain will first cause the sprocket 85 to be rotated torotatethe pinions 83 and thereby transmit a rotary motion to the shaft11 in a clockwise direction. This will cause the right-hand" scraper asviewed in Figure 12 to swing down and the left-hand scraper to swing up.When the left-hand scraper I9 has come up against the left-hand stop 88,the shaft 82 provided with an adjustable stop III to limit the downwardtravel thereof so that after a blade has lowered to a predeterminedextent, it will be stopped.

Parallel sprocket chains I02 are employed which are driven in unison andwhich are reversible. The chain at each side of the carriage is guidedover guide sprockets and then over the cannot rotate further and thechain 86 will then be effective for moving the trolley in the reversedirection. When the direction of travel of the chain is again reversed,the shaft 82 will be rotated in the opposite direction and the scraperreturned to the position shown in Figure 12. A

limited relative movement between the trolley and the reversible drivingchain 86 is thus utilized for shifting the position of the scraper.

The arrangement shown in Figure 12 has an advantage over that previouslydescribed in that should it be necessary, the position of the scrapercan be shifted not only at the ends of the travel of the trolley, but atany intermediate point in the travel of the trolley.

It will be noted that with the arrangement shown in Figures 12, 13 and14, when the lefthand scraper 19 swings upwardly and the righthandscraper 1'8 swings downwardly, the righthand scraper will come intoposition against the opposite side of the pile. In order to prevent anyspilling over of the material with this type of scraper, a retainingplate 89 is provided at each side of the frame of the machine to extendfrom a point adjacent the form rail A to the underside of the frame.

For adjusting the scraper vertically I may raise and lower the runwayfor the trolley. This mechanism for raising and lowering the runway isshown in Figures 12 and 14 wherein there are threaded posts 16a at theend of the frame forming the runway which passes through nuts secured tothe frame and the lower ends of which are mounted in bearings on themain frame 2 of the machine. TWo posts are intergeared as illustrated sothat by turning a crank 18b secured to the top of one of the posts, bothof the threaded posts may be turned at the same time for raising orlowering the frame members which provide the runway.

My invention contemplates, therefore, that vertical adjustment of thescraper may be made either by adjusting the scraper vertically withrespect to the trolley or by raising and lowering,

a. portion of the machine, as for example,-the runway on which thetrolley is carried.

In the modification shown in Figure 15, 9| designates the runway for thetrolley 92. This trolley is provided with a shaft 93 having a sprocket94 at each end thereof. There are two scrapers 95 and 96 eachwith anupwardly extending portion 95a and 96a respectively thereon. Each ofthese upwardly extending portions carries a, rack 91. Guide rollers areprovided at 98 and'99. The shaft 93 is provided with a pair of pinionsHill which engages the rack 91 on both extensions. The arrangement issuch that when the sprockets 94 are rotated in one direction, one of theblades is lowered and one of them is raised, and when the direction ofrotation of the sprockets 94 is reversed, the position of the blades iscorrespondingly reversed. Each of the blades is main sprocket 94. Whenthe chain is moved in one direction the sprockets 94 are operated untilthe stop H on the descending blade contacts a part of the trolley whenthe sprocket cannot rotate further, and further operation of the chainserves to move the trolley along its runway. When the direction of thechains is reversed, the sprockets are turned in the opposite directionto reverse the blades, and after the sprockets have turned to reversethe blades, the pull of the chain is again utilized to move the trolley.In this modification as in the modification shown in Figures l2, l3 and14 there is a relative movement between the chain and the trolley whichis utilized for shifting the blades.

While the blades in the two modifications described are illustrated asbeing parallel with the direction of travel of the machine, that is,transverse to the direction of movement of the trolley, it will beapparent that in these modifications the bladesmay also be set atopposite oblique angles so as to push the material forward as well assideways.

In using the machine, the scraper and the screed are set at the desiredelevation, the latter preferably slightly lower than the former. The

' screed is generally tilted crosswise of its length to a very slightangle so that the leading edge is slightly higher than the trailing edgeto more effectively iron or smooth out the material, the difference inelevation between the two edges being of the order of about A; of aninch and the adjustable links 24 enable the adjustment to the properangle to be established and maintained. Concrete is dumped between theforms for perhaps twenty or thirty feet in advance of the machine andample concrete is provided to assure of the desired depth of concretebeing spread. It is contemplated that there will al ways he an excess ofmaterial for the machine to spread in order to assure of all voids beingcompletely filled. The machine is then driven forward at a slow speedand as it is driven forward, the trolley is simultaneously driven backand forth to move the scraper transversely of the roadway. The forwardspeed of the machine is so correlated to the operation of the trolleythat the scraper will make overlapping passes or swaths crosswise of theroad as it travels back and forth. At any time the operator may stop theforward movement of the carriage and continue to operate the scraper, orhe can move the carriage without the scraper operating, the transmissionincluding various clutches forming no part of this invention forsecuring such selective operation. As the scraper or spreader moves backand forth it accumulates a pile of material at the places where theconcrete is piled up and spreads it into the valleys or recesses,completely filling in the space between the two forms to the desireddepth. At each limit of travel of the trolley the spreader pulls awayfrom one side of the pile that has accumulated and passes around or overthe pile so that as the trolley is moved along in the oppositedirection, the pile of material is pushed along in the oppositedirection,

some slight shifting of the material in the pile taking place if thescraper or spreader is of the vertically pivoted blade type as the bladesweeps around tospread close to the side rails. This pushing of thematerial back and forth not only prevents the material from being leftin heaps at the side of the pavement, but it produces a spreading actionnot unlike a troweling action which serves to compact the material.Because the scraper is a predetermined distance in front of the screedit will remove surplus material that would otherwise pile up in front ofthe screed. At the same time it does not prevent a slight excess fromaccumulating at the front of the screed as some excess is desirable. Inthe process of paving, the screed is moved along as the material isworked back and forth, and a. substantially controlled amount of surplusmaterial is maintained in front of the screed uniformly across itswidth. As previously stated, this is important because in a pavingoperation the material rises to a slight extent to the rear of thescreed r strike-off, and this varies according to the surplus in frontof the strike-oil. By maintaining a controlled volume of material infront of the strike-off and keeping it distributed uniformly across thefront ,of the strike-off, the material back of the strike-off raisesmore uniformly, eliminating those transverse or longitudinal waves orripples that result where the amount of material in front of thestrike-oil is continually varying.

Usually in the laying of a roadway an initial layer of concrete will beput down to within perhaps 2" of the top of the forms after whichreinforcing may be laid and then a finishing layer of concrete put downon the reinforcing. By reason of the vertical adjustment of the scraperand the screed of the machine described, it is possible for the onemachine to perform both operations or it is possible for a contractor touse two similar machines one following the other. Where one machine isused to do both operations, the scraper and the screed may be liftedclear of the paved surface when the machine is traveling backward to thepoint where it begins to spread the second layer.

An important advantage of the present invention is in the provision of aspreader which works the material back and forth transversely of theroadway. Another important advantage is that by making the spreader orscraper blade oblique to the direction of travel of the trolley, thematerial may be simultaneously worked sideways and forwardly. Stillanother advantage is that the scraper will spread the material clear upto the side rails but will not leave the material in heaps adjacent theside rails. It should be noted that while the carriage moves a distanceless than the full distance between the rails, the scraper in any casereaches beyond the limits of travel of the carriage to the rails due tothe relative movement which occurs between the carriage and the scrapingmeans. It is by this overreaching movement that the pile of material canbe pushed across the full width of the area to be paved and then engagedfrom the opposite side and moved in the reverse direction. By combiningthe transversely moving scraper with a screed, particularly a vibratingscreed, it is possible to prevent the uneven piling of material in frontof the screed and at the same time assure of there always being asufiicient excess for the best results to be secured. The invention thusconsiderably facilitates the laying of roads and the carrying out ofsimilar paving operations.

While I have illustrated and described certain embodiments of myinvention, it will be understood that this is by way of illustration andthat various changes and modifications may be made in the machine withinthe contemplation of my invention and under the scope of the followingclaims.

I claim:

1. A spreader for concrete paving operations comprising a mobilesupporting frame, a spreader mounted on the frame for movement back andforth across the frame transverse to the direction in which the frame ismoved, means for raising and lowering the elevation of the spreader,means for driving the spreader, and means for imparting an overreachingmovement to the spreader relative to said driving means adjacent eachlimit of its back and forth travel to transpose the position of thespreader from one side of the pile of material being spread to theopposite side.

2. A spreader for concrete paving operations comprising a. wheeledsupporting frame, the wheels of which are adapted for travel along railsat each side of the pavement to be constructed, a spreader membersupported on the frame and movable back and forth in a rectilineardirection between the rails, means for driving the spreader, and meansfor imparting an effective overreaching movement to the spreaderadjacent each limit of its travel.

3. A spreader for concrete paving operations comprising a mobilesupporting frame, a spreader carried on the frame and movable back andforth across the frame, means for driving the spreader back and forth,and automatic means for shifting the spreader relatively to the materialbeing pushed by the spreader to extend the effective sweep of thespreader at the limits of its travel beyond the range of the actual backand forth movements thereof.

4. A spreader for concrete paving operations comprising a mobilesupporting frame, a carriage on the frame and movable back and forthacross the frame, means for moving the carriage back and forth,spreading means carried by the carriage and means for shifting thespreader means relatively to the carriage from one operating position toanother operating position more remote from the center of the roadadjacent each limit of travel of the carriage.

5. A spreader for concrete paving operations comprising a mobilesupporting frame, a carrier on the frame movable back and forth acrossthe frame, means for driving said carrier back and forth, spreadingmeans depending from said porting frame, a trolley on said frame movableback and forth across the width thereof, scraper means pivotally carriedon the trolley, and means for turning the scraper means about itspivotal axis to substantially reverse the position of the scraper meansend-for-end adjacent the limits of travel of the trolley.

back and forth across the width thereof, scraper means pivotally carriedon the trolley, means for driving the trolley back and forth, and meansfor moving the scraper means about its pivot adjacent the limits oftravel of the trolley and before the trolley reaches the limit of itstravel.

8. A paving machine of the class described. comprising a wheeled framehaving a strike-off member extending transversely across it, a spreadermovable transversely back and forth in front of the strike-off at aspaced distance therefrom but sumciently close thereto to engage excesssurplus material that accumulates in front of the strike-off, saidspreader being set oblique advance of the opposite end,means for'drivingthe spreader and means for reversing the angular position of thespreader with its change in direc tion of travel. '9. A road pavingmachine comprising a momaterial in front of the strike-o8 andredistribute it in the space to be paved forwardly of the strike-off.

10. A road paving machine comprising a mobile truck adapted to travel onforms at each side of the area to be paved, a transverse runway on thetruck, a carrier movable along the runway, a support depending from thecarrier, a

paddle-like spreader on the support set edgewise to the surface to bepaved, means for moving the carrier back and forth whereby the spreaderis caused to effect a preliminary distribution of the to its directionof travel with the end of the spreader closest the strike-off beingnormally in paving materialwhich may be irregularly heaped in the spacebetween the side forms, said spreader being movable relatively to thecarrier in a manner such as to overreach the travel occasioned by theback and forth movement of the carrier, and means for imparting suchrelative movement to the spreader adjacent the limits of bile truckadapted to travel on forms at each paddle-like spreader on the supportset edgewise to the surface to be paved, means for moving the carrierback and forth whereby the spreader is caused to effect a preliminarydistribution of the paving material which may be irregularly heaped inthe space between the side forms, and transtravel of the carrier tothereby project the spreaderbeyond the pile of material being pushed byit and engage it from the opposite direction.

11. In a concrete paving machine having a supporting frame spanning astrip to be paved and movable along said strip, a carriage mounted onsaid frame for movement transversely of said strip, mechanism carried bysaid carriage and adaptedto push a deep pile of concrete in a directionhaving a component in the direction of movement of said carriage, saidmechanism being shiftably mounted in said carriage to selectively engagesaid pile from either side of said pile,

' means for moving said carriage to-and-fro across verse strike-offmeans on the truck rearwardlyof the spreader for effecting a furtherandcomplementary paving operation, said spreader be.- ing arranged withreference to the strike-off in such manner. as to also carry away excesssurplus said frame, and means for shifting said mechanism to engage theopposite side of said pile when said carriage is adjacent the limits ofits travel.

EDWARD L. HARRINGTON.

